Council Directive 98/83/EC of 3 November 1998 on the quality of water intended for human consumption
[1. Sampling points shall be determined so as to ensure compliance with the points of compliance as defined in Article 6(1). In the case of a distribution network, a Member State may take samples within the supply zone or at the treatment works for particular parameters if it can be demonstrated that there would be no adverse change to the measured value of the parameters concerned. As far as possible, the number of samples shall be distributed equally in time and location.] U.K.
